నైరూప్య

Diagnosing pulmonary tuberculosis with fibre-optic bronchoscopy and its significant role

Debra Griffin

 

  The 1990 World Health Organization (WHO) report on the Global Burden of Disease ranked tuberculosis as the seventh most morbidity-causing disease in the world, and expected it to continue in the same position up to 2020. Someone somewhere contracts tuberculosis every four seconds and one of them dies every 10 seconds. In 2006, about 1.4 million cases of tuberculosis were registered for treatment in India; 28.7% of them were new smear negative cases. The initial diagnostic approach to suspected cases of pulmonary tuberculosis is to demonstrate Mycobacterium tuberculosis in stained smears of expectorated sputum. In most of the tuberculosis centers, even after meticulous search, the bacteriological positive yield from sputum is around 16 to 50% and large portion remain negative in spite of clinical profile and radiological lesions being consistent with diagnosis of pulmonary tuberculosis. Early diagnosis of pulmonary tuberculosis prevents progression of disease, morbidity, spread of disease and permanent damage by fibrosis. Culture of sputum for acid fast bacilli (AFB) takes long time and a reliable serological test is not yet available. In such a situation bronchoscopy has been tried for rapid diagnosis of tuberculosis in smear negative cases. Fibreoptic bronchoscopy with bronchial washing analysis for AFB including culture for Mycobacterium tuberculosis has significant role to establish the diagnosis when extensive search for AFB in expectorated sputum has repeatedly failed, when sputum expectoration is absent or sputum induction has failed. The present study aims to assess the role of fibreoptic bronchoscopy in the diagnosis of sputum/smearnegative pulmonary tuberculosis. The present study, approved by the institutional ethics committee, was conducted in the Department of Pulmonary Medicine. Clinically suspected cases of pulmonary tuberculosis, aged 16-75 years, with three sputum smears negative for AFB and a chest radiograph suggestive of pulmonary tuberculosis were included in the study after obtaining an informed consent. Patients with bleeding diathesis, history of myocardial infarction or arrhythmia, extra-pulmonary tuberculosis, history of anti-tubercular treatment (ATT) for more than one month, and those with severe dyspnoea were excluded from the study. HIV-positive and non-cooperative patients were also excluded. A detailed history, clinical examination, and routine investigations were carried out on suspected cases of tuberculosis. Three sputum samples (spot, morning and spot) were tested for presence of AFB in the smear. In patients with suspected smear negative pulmonary tuberculosis, a sputum sample was sent for sputum culture (BACTEC) and the patients were taken up for bronchoscopy. Prior to the procedure an informed written consent was obtained from the patient. The procedure was carried out electively with the patient nil orally for four to six hours. Patients were pre-medicated 30-45 minutes